Broken text after text being extruded
There is no need to convert text or curves to mesh to extrude.
Curves converted to mesh will en up in bad topology most of the time... If there are overlapping segments then you will have errors like the ones shown on the question.
Use the Extrude settings in the Geometry section of the text controls in the properties window.


And please don't use photos from your phone, use screen captures, they are more readable